Serum interleukin-6 level is reflected in elevated high-sensitivity C-reactive protein level in patients with systemic sclerosis.

Systemic sclerosis (SSc) is a systemic connective tissue disease of unknown etiology which presents immunological, vascular and connective tissue abnormalities. Serum interleukin (IL)-6 has been reported to be elevated in patients with SSc. Clinical and laboratory findings affecting the elevated level of high-sensitivity C-reactive protein (hs-CRP) were studied in patients with SSc. Clinical and laboratory findings also included serum IL-6 level. Thirty-nine SSc patients (male : female = 7:32, age 19-84 years, mean 62.6 years) were studied. hs-CRP was measured with a nephelometric assay. Serum IL-6 level was measured by enzyme-linked immunosorbent assay. The distributions of hs-CRP showed that 18 cases (46.2%) were not elevated (<0.07 mg/dL), but 21 cases (53.8%) were (≥0.07 mg/dL). Alkaline phosphatase and IL-6 in SSc patients with elevated hs-CRP (291 ± 95 U/L, 3.23 ± 2.74 pg/mL) were significantly more elevated than those in not elevated patients (221 ± 75 U/L, 1.53 ± 1.12 pg/mL) (P < 0.02, P < 0.01). The correlation between hs-CRP level and IL-6 level in SSc patients was 0.687 (P < 0.001). In conclusion, elevated serum IL-6 levels are reflected in elevated hs-CRP levels in SSc patients.